Pressure gauge



Jan. 27, 1942. w. H. LoNGsTREE-r PRESSURE GAUGE Filed March 2, 1939 2Sheets-Sheet l i im:

i .gnomi/TM Gila/@5522@ J@- 27, 1942- W. H. LoNGsTREE-r 2,271,268

PRESSURE GAUGE Patented Jan. 27, 1942 UNITED STATES; PATENT OFFICEPRESSURE GAUGE Walter H. Longstreet, Brooklyn, N. Y., assignerv to AcmeAir Appliance Company, Inc., Brooklyn, N. Y., a corporation of New YorkApplication March 2, 1939, Serial No. 259,457

13 claims. (o1. vs-m) The present invention relates generally topressure gauges, and more particularly gauges of the dial type used ingauging tire, tank and other pleSSuIeS.

An object of the present invention is to provide a pressure gauge of thetype described that is simple in construction, economical tomanufacture, and capable of easy and convenient assembly or replacementof parts without the use of tools.

Another object is the utilizationof pointer normalizing means to alsoretain the indicating unit lin position in the casing during assembly ofthe parts.

A further object is the provision of a completely molded preferablynon-metallic casing including an integral pressure cylinder.

Another object is the provision of spring means disposed on theindicating unit assembly to cooperate with the under surface of the dialfor holding the indicator unit in position and provide the necessaryfrictional pressure for retaining the pointer in pressure-indicatingposition after a pressure gauging operation.

A further object resides in the utilization of a backing or closureplate cooperating with a plunger actuating plate carried. by the pistonto retain the actuating plate in operative position on the piston. y

A further object is to provide a cup-shaped -piston and cooperatingguide stem seated in opposite sides of the casing and telescopicallyarranged with a direct acting spring interposed therebetween, permittingthe employment of an extra long coil spring, which, due toits length, 2

while the pistoncup is in contact with theexo panding means.

Other and further objects and advantages of the invention will behereinafter set forth and the novel features thereof dened by theappended claims. l

In the drawings:

Figure 1 is a front elevation of a pressure gauge embodying the featuresof my invention.

Figure 2 is an elevation of the gauge shown in 'Figure 1 but with thetransparent closure, its

retaining bezel-ring, and the dial removed and parts being broken away,the dotted lines illustratingthe normalizing plunger depressed torestore the indicator after a pressure reading has been made;V

Figure 3 discloses the indicator unit, its operating linkvconnection,and the associated removable plunger engaging plate;

Figure 4 is a vertical sectional view through the piston assembly unit;

Figure 5 is a vertical sectional view taken approximately on the planeindicated by line 5-5 of Figure 2 looking in the direction of thearrows;

Figurev 6 is a similar View taken approximately on the plane indicatedby line 6--6 of Figure 2, certain of the parts being shown in elevation;

and f Figure 7 is a horizontal sectional View taken approximately on theline I'1 of Figure 2 and looking-inthe direction of the arrows.

Like reference characters designate Corresponding parts in the severalfigures of the drawings.

Referring to the drawings, my improved pressure gauge includes a shallowcylindrical casing I molded of suitable, preferably non-metallic,material vwith anv annular bezel-ring retaining shoulder 2 of theannular wall 3 outstanding from the back wall 4.

The interior of the casing I is formed with a somewhat elongated andrectangular enlargement extending from the backl wall and the annularwall toward the center of the casing. This enlargement is formed withthe bore-5 extending completely therethroughfrom a point substancatingunit thereon, designated generally by the numeral 8. A U-shapedbaseplate 9 seated in the grooves 'I is provided with a post II) projectingA therefrom on which the pointer II is freely pivoted. The blade portionof the pointer is retained between the spaced shoulders IZa-IZa formedon the lever I2 which in turn is pivotally mounted on the post I0.

The lever I-2 is apertured at I2C and receives the bent extremity Ida ofthe link I 4.

The link rod I4 is provided with a head portion Mb for engagement with asocket I5 in the piston plunger operating plate I6 later to bedescribed.

Referring again to the indicator unit, the lever I2 is formed with apointer normalizing tail portion I2b by means of which the pointer isreturned to zero position after a pressure reading as will be laterdescribed.

The plate I6 is arranged to interlockingly engage the plunger I1 of thepiston assembly unit, as seen more particularly in Figure 4.

This piston assembly comprises the piston plunger I1 of hollowcylindrical formation fairly closely fitting the wall of the cylinder 5.The upper end of the plunger I'I is formed with an annular groove I'Iato receive the plate I8 as stated above, the plate being of a thicknesscorresponding to approximately the width of the groove and having aU-shaped slot I6a extending inwardly from one edge for interlockinglyengaging the groove of the plunger.

The plate I5 thus engages the end of the enlargement containing thecylinder and thereby constitutes stop means for limiting outwardmovement of the plunger II. 'l

The plunger piston I1 carries a cup Washer or leather I9 disposed on itsend, and retained thereon, as seen in Figure 4, by the guide extensionIIb suitably secured to the plunger.

A coil spring 20 is disposed within the plunger II, one end thereofbeing seated on the closed end of the plunger I1. The other end of thespring receives or surrounds a hollow spring and plunger-guide-stem 2I,the upper end 2Ia of f which is flared outwardly and rests in the seat 6of the casing. This guide stem projects toward the plunger I'I to apoint adjacent the same when the plunger is in normal position supportedby the plate I6, so that, upon inward move- L ment of the plunger Il, ittelescopes over the guide stem 2| with the spring 29 in between theinner surface of the plunger and the outer surface of the guide stem.

As before pointed out, the plate I6 disposed in the groove I'Ia on thepiston plunger I'I limits the outward movement of the plunger underinfluence of the spring 29, which due to the hollow plungerconstruction, extends substantially entirely across the casing I. Theuse of this relatively long coil spring permits the wire gauge andnumber of coils to be accurately determined for the desired opposingpressure on the piston.

The valve nipple 22, as seen in Figure 6 of the drawings, is formed witha beveled extremity 22a for engaging and expanding the free edge of thepiston plunger leather I9 into contact with the cylinder wall.

The nipple 22 is tapered inwardly, as at 2222, to receive the valvechuck portion 23. This arrangement permits the chuck head 23 to berotatably adjusted with respect to the gauge as desired.

Referring to Figures 2 and 7, the lcasing is formed with a slotted post24 arranged to receive the normalizing spring 25. One end of this springis interposed in the slot, and, after being spirally looped around thepost adjacent the base of the casing, is bent at right angles outwardlyto be received in the cross slot 26a of the normalizing plunger 26. Thespring, yafter passing through this slot, is again bent at right anglesto project outwardly across the plate 9 to a point adjacent the tailpiece I2b of the lever I2. The tension of the spring normally maintainsthe normalizing plunger 25 in its projected position, as shown in Figure2, with the bent extremity 25a disposed in slightly spaced relation tothe tail piece I2b so as to permit actuation of the pointer and lever bythe piston without any engagement of the lever I2 with the extremity 25aduring pressure gauging.

The spring 25 also retains the plate 9 in the recess 1 formed in theenlargement containing the pressure cylinder during the assembly of thedevice and before the cover and dial are assembled to prevent accidentaldisplacement of the plate 9 `from its seat in the groove 1.

Inward manual pressure on the normalizing plunger 26 causes the bentextremity 25a to engage the tail piece of the lever I2 and thus swingthe indicator or pointer II to the left to zero position,

The plate I6 is retained against accidental displacement from the pistonplunger I'I by the backing plate 21 which is semi-circular in form andseated on a suitable ledge and shoulders Ia molded in the casing I.Since this plate is directly in front of the piston and about on a planewith the front of the enlargement containing the pressure cylinder, itwill be observed that after the plate I6 has been introduced on theplunger il this semi-circular backing plate 21 limits any displacementmovement of the plate IB from the plunger. The plate 21 also forms aclosure for the inner portion of the casing and a background for thepointer I I.

The plate 21 is retained on its ledge by a semicircular spacer strip orspring 28 which extends around one-half of the casing I between theshoulders Ia.

The main or indicia dial 29 rests on this strip 25 and on a slight ledge3a of the Wall 3. This dial is provided with inwardly bent tabs 29a vand29D adapted to be received in corresponding notches Ib and Ic formed inthe casing I.

The dial 29 forms a closure member for the open side of the casing andhas an indicator sight opening 29e through which the pointer is Visibleafter a pressure reading, as seen in Figure l. Suitable pressureindicating indicia 29d in pounds per square inch, or indicia 29e inkilos per cubic centimeter may be provided adjacent the sight opening29C. f

A suitable transparent closure 39, preferably of a flexible ornon-breakable nature, is provided, as shown in Figures 5 and 6. Thisclosure rests on the dial closure member 29 and retains the same inposition in the casing. The ring bezel SI frictionally engages theexterior of the casing, and, when seated on the shoulder 2, retains themain dial 29, and, through the strip 28 the backing plate 2, which platein turn retains the plate I6 on the plunger II. The dial 29 also retainsthe pointer unit in position on the enlargement in the casing.

The indicator unit, as seen in Figures 2 and 6. carries a leaf springI3, the outer portions I3a of which engage the under face of the dialclosure member 29 exerting a seating pressure on the indicator assemblyand maintaining the U-shaped clip 9 seated in the grooves 'I of thecylinder enlargement in the casing.

One end of this leaf spring is seated in the notch Ic of the casingpreventing any relative rotary movement of this spring. This spring I3also exerts a friction pressure on the lever I2 and pointer II, sincethe spring I3 presses the lever I2 and pointer II against the spacingwasher Ia on the post IB, and the relative friction between these partsis suii'icient to retain the pointer in adjusted position after apressure reading.

In the operation of the gauge, the chuck 23 is pressed onto the valvestem of a pressure fluid container, such as a pneumatic tire or tank,which depresses the valve in the usual manner, permitting the pressurefluid to pass through the chuck stem and the nipple 23 into the cylinderof the gauge forcing the piston plunger I1 upwardly causing the pistonplunger, the guide stem 2| and the coil spring 20 to telescope. As thepiston plunger moves upwardly, the head I4b of the link I4 engages thestop plate IB rocking the lever I2 to the right, as seen in Figure 2.The pointer II carried by the lever l2 moves across behind the opening29e in the dial 29. The gauge may then be removed from the valve stemwhereupon the piston will again be forced outwardly by the springcarrying the stop plate along with it. However, the pointer will notmove back due to the sliding connection between the e stop plate and thelink rod I4. The leaf spring engaging the rear face of the dial exertssufficient pressure on the indicator lever to frictionally hold the samein its adjusted position. By observing the relation of the pointer I Iwith respect to the indicia on the dial 29, the pressure in the tank ortire previously gauged may be noted. Referring to Figure 1, the pointerII indicates 32.5 pounds. In order to restore the pointer for subsequentgauging operations, the plunger 26 is pressed inwardly causing theupwardly bent extremity 25a 'of the spring 25 to engage the tail pieceI2b of the lever I2, rocking the same to the left as shown in dottedlines in Figure 2.

In order to dismantle the device, the bezelring 2 is first pried off ofthe casing which permits ready withdrawal of the dial 29, whereupon thesemi-circular spacer spring 28 may be snapped out of the casingreleasing the semicircular backing plate 21 which may be removed. Afterthe backing plate is displaced, the stop plate on the piston is readilyremoved therefrom, and by displacing the free end 25a. of the spring 25slightly the indicator unit may be removed from the cylinder along withthe plate. Swinging the link member I4 backwardly disengages the samefrom the aperture I2c in the end of the lever I2, whereupon this linkmay be withdrawn from the plate I6. Unscrewing of the nipple 22 nowpermits withdrawal of the piston, the spring, and the guide stem 2|vfrom the casing. The

curved retainer spring fitted in the slot of the post 24 may be liftedout, thus releasing the normalizing spring 25, which, afterdisengagement from the slot 26a of the plunger 26, may be lifted off ofthe post, Upon pressing inwardly on the plunger 26 this plunger may bewithdrawn from its seat in the casing.

In the assembly of the device, the reverse operation takes place, and itwill be observed that the device may, therefore, be readily assembledwithout the use of any tools whatsoever. Due to the elongated cup-shapedpiston having its base disposed adjacent one side of the casing and thespring seat at the opposite side, an extremely long coil spring isemployed which permits much easier calibration and correspondinglyincreased accuracy in the gauge than in the previous types of gaugeswhere much shorter or smaller springs are used. The use of the guidestem telescopingly arranged with respect to the bore of the piston andthe coil spring interposed therebetween permits an accurate guiding oraxial movement of the piston and spring during a gauging operation, andthe cooperation of the piston guide extension with the socket in thenipple positively supports the packing end of the piston centrallywithin the cylinder and with relation to the piston packing expandingmeans on the end of the nipple. Also, the disposition of the stop plateon the end of the piston limits the outward movement of the pistontoward theexpanding means, and, therefore, prevents undue pressure onthe expanded packing cup I9. In assembled position it should againy beobserved that the semicircular backing plate 21 effectively preventsremoval of the stop plate from the piston. Also, it prevents removal ofthe curved spring disposed in the post 24. The dial retains this backingplate in position and also by its engagement with the opposite ends ofthe leaf spring I3 retains the indicator unit firmly seated in itssocket on the cylinder.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a pressure gauge of the class described, a casing, a pressurecylinder formed therein having an exterior groove thereon, a pistonplunger operable within said cylinder, an indicator device detacha'b-lydisposed on said cylinder including a supporting plate having spacedarms engaging about said cylinder and disposed in the said groove, apointer carried by said plate, and an operating connection between saidpiston plunger and said pointer for moving the pointer.

2. In a pressure gauge of the class described, a casing, having a springreceiving seat at one side, a cylinder within said casing at the otherlside thereof, a piston having a hollow plunger extending into saidcylinder, stop means for limiting movement of said piston plungeroutwardly of said casing, pressure indicating means operable by saidstop means, and spring means seated in the hollow plunger at one end andin said casing spring seat at its other end for moving the plungeroutwardly.

3. In a gauge of the class described, a casing e having a cylinderformed therein at one side and a spring seat in the wall of the casingat the opposite side, an elongated hollow plunger disposed in saidycylinder with the head of the plunger adjacent the wall opposite fromsaid spring seat, a` plunger and spring guide in the said spring seatprojecting axially toward the mouth of said plunger and arranged to beltelescoped relative to the plunger upon inward movement of said plunger,a compression coil spring extending substantially across said casing anddisposed about said guide and in said plunger, removable stop means onthe plunger for limiting movement of the plunger toward the exterior ofthe casing, and an indicator unit slidablx7 connected to said stop meansto be operated thereby.

4. In a pressure gauge of the class described, a molded non-metallicone-piece casing including a cylinder formed therein, a hollow plungerextending into said cylinder having an exterior groove formed thereinadjacent one end thereof. an operating plate seated in said groove, anindicator mounted on said cylinder, an actuating connection between saidindicator and said plate comprising a link member connected totheindicator and slidingly engaging said plate and formed with a shoulderfor engaging said plate upon movement thereof in one direction to movethe indicator in one direction, separate means for moving the indicatorin the opposite direction, and a coil spring extending across the casingand seated at one end in said hollow plunger and at the other end on theinner wall of the casing.

5. In a pressure gauge of the class described, a casing, a cylinderwithin said casing, a hollow plunger extending into said cylinder havinga flexible cup-shaped piston packing at its outer end, a packingspreader in the mouth of said cylinder, a stop plate detachabliT securedto the inner end of said plunger and engageable with said cylinder tolimit the outward movement of said plunger toward said packing spreader,and a coil `spring seated at one end on the wall of the casing and insaid plunger at its other end to urge said plunger toward said packingspreader.

6. In a pressure gauge of the class described, a casing having apressure cylinder, a plunger having a piston operable within saidcylinder, an indicator unit disposed on said cylinder comprising a clipmember interlocking with the sides of said cylinder, an indicatorpivotally mounted on said clip, an apertured plate carried by saidplunger, an operating link connected to said indicator and passingthrough the aperture of said plate and having an enlargement thereonengageable with one side of said plate upon movement of the piston inone direction to move the indicator in said direction only, and separatemeans for moving said indicator in the opposite direction.

'7. In a gauge of the class described, a casing open at one side havinga cylinder' therein, a plunger having a piston operable within saidcylinder, readily displaceable stop means on said plunger for limitingoutward movement of said piston and removable through said opening insaid casing, means for exerting outward pressure on said plunger to seatsaid stop means on the inner end of the cylinder, a pointer within thecasing, an operating connection between the pointer and the stop means,and a backing plate disposed in the casing for retaining said stop meansagainst displacement on said plunger.

8. In a gauge of the class described, a casing open at one side having acylinder therein, a plunger having a piston operable within saidcylinder, readily displaceable stop means interlockingly engaging saidplunger for limiting outward movement of said piston and removable'through the opening in said casing means for exerting outward pressureon said plunger to seat said stop means on the inner end of thecylinder, a pointer within the casing, an operating connection betweenthe pointer .and the stop means, a backing plate removably disposed inthe casing for retaining said stop means against displacement on saidplunger, and an indicia carrying dial cooperating with said pointer .anddisposed operative position in said casing.

9. In a pressure gauge, a casing, having a cylinder therein, anindicator unit within the casing, a hollow plunger operable in saidcylinder formed with a guide extension and a piston cup washer at itsouter end, plunger stop means removably disposed on the other end ofsaid on said casing to retain said backing plate in "[69 plunger tolimit outward movement of sai/d plunger, an air chuck nipple extendinginto the outer end of the cylinder and having means thereon forexpanding the cup washer toward the walls of the cylinder, and formedwith a guide extension receiving socket to receive the guide extensionof the plunger and prevent lateral displacement of the outer end of theplunger when the cup washer is in engagement with said expanding means.l

l0. In a pressure gauge, .a casing, a pressure cylinder within saidcasing, an indicator support removably seated on said cylinder, anindicator shiftably carried by said indicator support, an indicatoroperating piston within said cylinder, link means slidably connectingsaid piston to said indicator having a head at one end engageable withsaid indicator to move the same in one direction only upon movement ofthe piston and a manually shiftable indicator return element carried bysaid casing `and having a portion overlying and engaging said indicatorsupport to prevent movement of said indicator support away from its seaton said cylinder.

11. In a pressure gauge, a casing, a pressure cylinder therein, anadjustable indicato-r within said casing, piston means within saidcylinder for operating said indicator, a link member connected at oneend to said indicator and formed with an actuating head at its other endengageable with said piston means to actuate the indicator upon movementof the piston means in one direction only, friction means within saidcasing engaging said indicator to hold the indicator in its .adjustedpositions, and means for zeroizing said indicator.

l2. In a pressure gauge of the class described, a casing open at oneside and having an indicator unit supporting cylinder formed therein, adial closure member for the open side of said casing, a piston operablein said cylinder, an indicator unit including a support removably seatedon said cylinder, a pointer pivoted on the support and spring means onsaid support between said pointer and dial closure member andfrictionally engaging said pointer to hold said pointer in itsresponsive positions, and an operating connection between said pistonand said indicator to operate said pointer in one direction, and meansfor zeroizing said pointer.

13. In a pressure gauge, an open sided casing having a cylinder formedtherein, a removable closure for said casing including an indiciacarrying dial and means for retaining said dial on said casing, a pistonoperable within said cylinder, an indicator unit removably seated in thecasing on said cylinder, said unit including a shiftable pointeradjustable to different positions relative to said indicia carryingdial, means connecting said piston tov said pointer for operating saidpointer in one direction, resilient means between the pointer and saiddial tensioning said indicator unit toward its seat on the cylinder andfrictionally engaging said pointer to hold the same in its adjustedpositions, and means for zeroizing said pointer.

WALTER H. LONGSTREET.

